The present invention relates generally to vehicle components, and more particularly, to shackle assemblies used to connect vehicle suspension components to a vehicle frame.
Shackle assemblies are typically used in a variety of vehicle suspensions to connect vehicle suspension components to a vehicle frame. Conventional shackle assemblies are typically used in leaf spring front suspensions, but typically do not use elastomer bushings. In a conventional shackle assembly, the suspension side loads are carried through the conical loading of the non-rubber bushings through the shackle plates. These shackle assemblies primarily rely on the bushing properties and shackle plate stiffness to provide for suspension lateral and conical stiffness.
One recognized problem of conventional shackle assemblies is their ineffectiveness in providing sufficient suspension lateral and conical stiffness, primarily due to the large distance spanned between the shackle plates. Conventional assemblies cause the suspension to be laterally compliant due to conical deflections in the bushings and bending in the shackle plates.
In order to accommodate for this lateral stiffness, conventional shackle assemblies ordinarily rely on the uniform rigidity and shape of the non-rubber bushings and/or shackle plates to react to side loads. Those skilled in the art will recognize that conventional shackle assemblies require strong, stiff, heavy, and, therefore, costly bushings and shackle plates. Those skilled in the art will further recognize that the non-rubber (i.e., strictly metal) bushings used in conventional assemblies are unable to provide vertical compliance. Accordingly, conventional shackle assemblies could undesirably induce compressive stress in the leaf spring.
Another item not present in the prior art is that conventional shackle assemblies typically do not incorporate built-in redundancy features to help provide vehicle control in the event of a broken spring. Suspensions utilizing conventional shackle assemblies traditionally require an additional leaf with “military wrap.” Those skilled in the art will recognize that these and similar redundancy features add cost, weight, and complexity to the suspension.
In view of the foregoing, it is desirable to develop a shackle assembly that provides sufficient suspension lateral and conical stiffness.
It is further desirable to develop a shackle assembly that reduces the reliance on the uniform rigidity and shape of bushings and shackle plates to react to side loads.
It is further desirable to develop a shackle assembly that allows for lighter, and, therefore, less costly bushings and shackle plates to be incorporated as component parts thereof.
It is further desirable to develop a shackle assembly having versatile, elastomer bushings with voids oriented to enhance vertical, conical and torsional performance.
It is further desirable to design a shackle assembly that permits additional suspension travel during rebound, or an overhang condition (i.e., an extreme rebound condition).
It is further desirable to develop a shackle assembly that comprises light, and, therefore, low cost redundancy features.
It is further desirable to develop a shackle assembly that incorporates built-in redundancy features.
It is further desirable to develop a shackle assembly that may be accommodated by any conventional leaf spring suspension system (front and/or rear), and at the front and/or rear end of the leaf spring.
These and other desired benefits of the preferred forms of the invention will become apparent from the following description. It will be understood, however, that a device or assembly could still appropriate the claimed invention without accomplishing each and every one of these desired benefits, including those gleaned from the following description. The appended claims, not these desired benefits, define the subject matter of the invention. Any and all benefits are derived from the preferred forms of-the invention, not necessarily the invention in general.